alpha_train --seed is clap-typed as u64, and clap's default u64
parser only accepts decimal digits. Previous default "0x4242"
hit "invalid digit found in string" at startup.
Replace with decimal equivalent 16962 (= 0x4242) in both the
submission script default and the workflow template default.
Long-term: could add a custom clap value_parser that accepts
hex/dec/oct prefixes, but for now decimal-only matches the
foxhunt convention in other CLIs (alpha_baseline, etc.).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>